title: Molecular analyses of Xenopus laevis Mesp-related genes.
abstract: During vertebrate somitogenesis, somites bud off from the anterior end of the presomitic mesoderm (PSM). Mesodermal posterior (Mesp)-related genes play essential roles in somitogenesis, particularly in the definition of the somite boundary position. Among vertebrates, two types of Mesp-related genes have been identified: Mesp1 and Mesp2 in the mouse; Meso-1 and Meso-2 in the chicken; Xl-mespa and Xl-mespb (also known as Thylacine1) in the African clawed frog (Xenopus laevis); and mesp-a and mesp-b in the zebrafish. However, the functional differences between two Mesp-related genes remain unknown. In the present study, we carried out comparative analyses of the Xl-mespa and Xl-mespb genes. The amino acid sequences of the Xl-mespa and Xl-mespb proteins showed a high level of similarity. The expression of Xl-mespa started broadly in the ventrolateral mesoderm and gradually shifted to a striped pattern of expression. In contrast, Xl-mespb showed a striped pattern of expression from the start. These expression profiles completely overlapped at the PSM during somitogenesis. To investigate the functional differences between Xl-mespa and Xl-mespb in terms of target gene regulation, we carried out a luciferase assay using the murine Lunatic fringe (L-fng) promoter. Transcription of the L-fng promoter was activated more strongly by Xl-mespb than by Xl-mespa. This same pattern was observed for the murine Mesp-related proteins. These results suggest that the functional differences between the two types of Mesp-related genes are evolutionally conserved in vertebrates.
authors.affiliation: Department of Life Sciences (Biology), Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hitachi
authors.forename: Akiko
authors.initials: A
authors.lastname: Kondow
authors.forename: Hiroki
authors.initials: H
authors.lastname: Danno
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Nishimura
authors.forename: Koji
authors.initials: K
authors.lastname: Okabayashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Asashima
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000235:genetics* / Q000378:metabolism*
chemical_list: D029867:Xenopus Proteins